Objective: Resistin, a novel cysteine-rich protein secreted by adipocytes, has been proposed to serve as a link between obesity and insulin resistance in rodents, but this has remained controversial. Most of the data obtained in previous studies are restricted to mRNA levels in tissues.
Design and patients: We examined the association between insulin resistance and circulating protein levels of resistin in 33 essential hypertensive patients (EHT) and 18 normotensive subjects (NT). Insulin sensitivity (M-value) was evaluated by the euglycaemic hyperinsulinaemic glucose clamp technique.
Results: Using a cutoff point of mean - 1 SD of the M-value in the NT, the EHT were divided into two groups: one group of 12 insulin-resistant patients (EHT-R) and one group of 21 noninsulin-resistant patients (EHT-N). There were no intergroup differences in age, gender, body mass index (BMI; range: 20.1-30.4 kg/m2), fasting glucose and total cholesterol. The EHT-R had significantly higher levels of fasting insulin and triglyceride than did the NT and the EHT-N. The EHT-R had higher levels of free fatty acid and lower levels of high-density lipoprotein cholesterol than did the EHT-N. The M-value was negatively correlated with fasting insulin, free fatty acid, and triglyceride. Circulating resistin levels were not significantly different among the three groups and were not correlated with the M-value, BMI, blood pressure, or lipid variables.
Conclusions: Our results suggest that circulating resistin levels are not related to insulin resistance, at least in patients with essential hypertension, although disturbance of lipid metabolism may be associated with insulin resistance.